The proposed study will continue our probe of the relationship between the glucocorticoid sulfotransferases -- STI, STII, and STIII --and biological glucocorticoid actions. We will finalize enzyme purification and immunochemical studies in progress; continue enzyme characterization, and both endocrine and nonendocrine control studies; relate STI, STII, and STIII to other important rat liver sulfotransferases and the ability of different organisms to respond to glucocorticoid. (A) STI purification will continue. Additional affinity chromatography methods will be used to purify the 1,000 to 1,250-fold purified enzyme to homogeneity. (B) Anti-STI will be prepared and used with anti-STIII, to develop a rapid immunochemical assay for tissue STI, STII, an STIII content. (C) STI and STIII characterization will continue. It will include mechanism studies, active site determinations, and subunit studies. (D) Study of endocrine control of glucocorticoid sulfotransferase production will continue. Pancreas, thyroid, and pituitary will be primary targets examined. Catecholamines, prostaglandins, and cyclic AMP will be among the other hormonal agents tested. These efforts will enlarge our understanding of endocrine control of STI, STII, and STIII production. (E) Effects of selected nonhormonal chemicals involved in physiological and pathological processes - upon sulfotransferase production - will be examined. An in-vitro screen will be attempted first. This will be followed by chronic injection studies wherein effects of test compounds on hepatic glucocorticoid sulfotransferases are evaluated. These studies may explain the impingement of test compounds on glucocorticoid actions. (F) Other important sulfotransferases of rat liver will be compared to STI, STII, and STIII. This will help us to ascertain the relation or lack of relation between the enzymes and simplify and clarify the information in the literature. (G) Comparison between glucocorticoid sulfotransferases present, the total glucocorticoid sulfotransferase activity, and ability to respond to glucocorticoid will be made in several species. Sections D-G will use enzyme fractionation and characterization, and immunochemical methods.